Anti-Biofouling Effect of PEG-Grafted Block Copolymer Synthesized by RAFT Polymerization.

Poly(glycidyl methadrylate-block-styrene) (PGMA-b-PS), a block copolymer consisting of glycidyl methacrylate and styrene, was synthesized via reversible addition-fragmentation chain transfer living polymerization. The synthesized PGMA-b-PS was then grafted with low-molecular-weight polyethylene glycol (PEG) via epoxy ring opening to give PGMA-g-PEG-b-PS, which was evaluated as an anti-biofouling coating material. As a preliminary test for the anti-biofouling effect, a protein adsorption experiment was performed on the synthesized block copolymer surface. The block copolymers were spin-coated onto silicon wafers, and protein adsorption experiments were carried out using fluorescein isothiocyanate conjugate-labeled bovine serum albumin. The fluorescence intensity of the protein adsorbed on the block copolymer surface was compared with that of a polystyrene film as a reference. The synthesized PGMA-g-PEG-b-PS film showed much lower fluorescence intensity than that of the PS film.

Uniaxial/biaxial flexure strengths and elastic properties of resin-composite block materials for CAD/CAM.

OBJECTIVE: Comparing strengths under different loading conditions provides useful information on the mechanical behaviour of restorative materials under multiaxial masticatory loading in the oral cavity. The aims of this study was to investigate the flexural strengths and the reliability of resin-composite blocks for CAD/CAM by uniaxial and biaxial flexure tests and to compare the elastic properties measured by different methods including digital image correlation (DIC). METHODS: Four resin-composite blocks for CAD/CAM, namely, VE (Vita Enamic), LU (Lava Ultimate), MD (Mazic Duro), and CS (Cerasmart), were investigated. Beam specimens (4.0×1.4×18.0mm3) and disks (12-14mmϕ×1.5mm) were prepared to determine the uniaxial (three-point bending) and biaxial (ball-on-ring, BOR) flexural strengths and flexural moduli. A compression test (8×4×18mm3) with DIC analysis was utilized to measure the elastic modulus and Poisson's ratio. Data were analysed by a 2-parameter Weibull function and ANOVA with Scheffe's test. RESULTS: The mean uniaxial and biaxial strengths and Weibull moduli of the specimen groups were as follows: uniaxial VE (140.1±7.0, 24.1), LU (159.1±6.3, 31.5), MD (144.9±13.3, 13.6), and CS (165.4±16.9, 11.2) and biaxial VE (153.6±10.4, 19.0), LU (231.0±29.3, 9.7), MD (148.9±23.8, 7.4), and CS (249.7±22.4, 13.8). Although the ranking of both sets of strength data remained unchanged, the strength reliability was significantly affected by the loading; the Weibull moduli of the specimens decreased when they were subjected to biaxial tests (except for that of CS). The elastic modulus values of the materials varied significantly under the different test loadings, although they were in the same order regardless of the test method: VE>>LU≈MD>CS. The DIC technique yielded elastic moduli that were in good agreement with those measured by the uniaxial flexure test. SIGNIFICANCE: The flexural strength, reliability, and elastic modulus of resin-composite block materials differed with the uniaxial and biaxial flexural loading and the test method. The different behaviours under both loadings should be considered in the evaluation of the mechanical performance of those materials.

Safety and efficacy of transluminal balloon angioplasty using a compliant balloon for severe cerebral vasospasm after an aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Vasospasm of cerebral vessels remains a major source of morbidity and mortality after an aneurysmal subarachnoid hemorrhage (SAH). The purpose of this study was to evaluate the safety and efficacy of transluminal balloon angioplasty (TBA) for SAH-induced vasospasm. METHODS: Eleven patients with an angiographically confirmed significant vasospasm (>50% vessel narrowing and clinical deterioration) were studied. A total of 54 vessel segments with significant vasospasm were treated by TBA. Digital subtraction angiography was used to confirm the presence of vasospasm, and TBA was performed to dilate vasospastic arteries. Medical and angiographic reports were reviewed to determine technical efficacy and for procedural complications. RESULTS: TBA using Hyper-Glide or Hyper-Form balloons (MicroTherapeutics, Irvine, CA) was successfully accomplished in 88.9% vasospastic segments (48 of 54), namely, in the distal internal carotid artery (100%, n=7), the middle cerebral artery (100%), including the M1 (n=10), M2 (n=10), and M3 segments (n=4), in the vertebral artery (100%, n=2), basilar artery (100%, n=1), and in the anterior cerebral artery (ACA), including the A1 (66%), A2 (66%), and A3 segments (100%). Vessel diameters significantly increased after TBA. There were no cases of vessel rupture or thromboembolic complications. GCS at one day after TBA showed an improvement in all patients except one. CONCLUSION: This study suggests that TBA using Hyper-Glide or Hyper-Form balloons is a safe and effective treatment for subarachnoid hemorrhage-induced cerebral vasospasm.

Urgent recanalization with stenting for severe intracranial atherosclerosis after transient ischemic attack or minor stroke.

OBJECTIVE: Stenting of symptomatic intracranial stenosis has recently become an alternative treatment modality. However, urgent intracranial stenting in patients with intracranial stenosis following a transient ischemic attack (TIA) or minor stroke is open to dispute. We sought to assess the feasibility, safety, and effectiveness of urgent intracranial stenting for severe stenosis (>70%) in TIA or minor stroke patients. METHODS: Between June 2009 and October 2010, stent-assisted angioplasty by using a balloon-expandable coronary stent for intracranial severe stenosis (>70%) was performed in 7 patients after TIA and 5 patients after minor stroke (14 stenotic lesions). Technical success rates, complications, angiographic findings, and clinical outcomes were retrospectively analyzed. RESULTS: Stenting was successful in all 12 patients. The mean time from symptom onset to stenting was 2.1 days (1-8 days). Post-procedural angiography showed restoration to a normal luminal diameter in all patients. In-stent thrombosis occurred in one patient (n=1, 8.3%), and was lysed with abciximab. No device-related complications, such as perforations or dissections at the target arteries or intracranial hemorrhaging, occurred in any patient. The mortality rate was 0%. No patient had an ischemic event over the mean follow-up period of 12.5 months (range, 7-21 months), and follow-up angiography (n=7) revealed no significant in-stent restenosis (>50%). CONCLUSION: Urgent recanalization with stenting is feasible, safe, and effective in patients with TIA or acute minor stroke with intracranial stenosis of ≥70%.

Endovascular graft-stent placement for treatment of traumatic carotid cavernous fistulas.

Detachable balloon-based endovascular fistula occlusion is a widely accepted treatment for traumatic carotid cavernous fistulas (CCF). However, more recently coils have been used to obliterate the lesion, especially in case detachable balloon is not available. We failed balloon-assisted coil embolization for CCF because of large fistulas and herniation of coil loops into the parent artery. The authors describe our experiences of balloonexpandable graft-stents to treat CCF, and place emphasis on arterial wall reconstruction. Three traumatic CCF patients were treated using a graft-stent with/without coils, and underwent angiographic follow-up to evaluate the patency of the internal carotid artery (ICA). In all cases, symptoms related to CCF regressed after stent deployment and did not recur during follow-up. Follow-up angiography revealed good patency of the ICA in all patients. Graft-stents should be considered as an alternative means of treating CCF and preserving the parent artery by arterial wall reconstruction especially in patients with a fistula that cannot be successfully occluded with detachable balloons or coils.

Reconstructive treatment using a stent graft for a dural arteriovenous fistula of the transverse sinus in the case of hypoplasia of the contralateral venous sinuses: technical case report.

OBJECTIVE: Transvenous coil embolization for transverse sinus (TS) and sigmoid sinus dural arteriovenous fistulae (DAVFs) is now recognized as one of the most effective treatment modalities. However, in the case of hypoplasia of the contralateral venous sinuses and internal jugular vein, complete occlusion of the ipsilateral sinus may cause fatal consequences. We describe a case of combined intravenous graft stent placement and transarterial coil embolization for DAVFs that involved the dominant right TS in a patient with hypoplasia of the contralateral venous sinuses. CLINICAL PRESENTATION: A 50-year-old man presented with headache, left hand tremor, and pulsatile right tinnitus. A cerebral angiogram demonstrated a right TS DAVF that was supplied by tentorial branches of both internal carotid arteries, multiple branches of the right external carotid artery, and branches of the left occipital artery. Unfortunately, left TS and sigmoid sinus hypoplasia were observed. INTERVENTION: A right TS balloon occlusion test revealed contrast stagnation of the cortical veins and of the right TS and superior sagittal sinus. In this case, the use of transvenous stent graft placement with or without transarterial embolization is safer and more effective than sacrifice of the right TS. We therefore performed balloon-expandable stent graft deployment at the right TS, and the remnant DAVF flow between the stent graft and venous sinus was treated with transarterial coil embolization. Postprocedural angiograms showed patent right TS outflow with disappearance of retrograde cortical venous drainage as well as complete eradication of the fistulous connections. CONCLUSION: In a DAVF involving the dominant TS or sigmoid sinus in a patient with hypoplasia of the contralateral venous sinuses and an intolerable balloon occlusion test for the ipsilateral venous sinuses, the complete occlusion of the diseased venous sinus may cause hazardous consequences. In this situation, the use of a stent graft with or without transarterial embolization to preserve venous sinus flow can be an effective treatment.